Check for common filenames that shouldn't be committed

[dlapiduz]

We should check for files like s3.yaml, secrets.yaml etc...

[marcesher]

@dlapiduz This is a fantastic idea! It should now be supported in the parse_commit branch.

What are well-known file names we should search for? I recommend we simply create a new file in clouseau's patterns directory, since clouseau supports passing multiple patterns files for a single run.

@lfatty will probably be able to help here, as well.